Such gear shifting devices in which the driver, or even an electronic device, selects only the gear desired and the shifting in the transmission itself is not carried out directly by the driver through a gear shift linkage, but by an auxiliary power actuated device for the coupling, are known in many embodiments; for example:
ZF-Typenblatt Electro-Pneumatic Shifting Device (ES) --Easyshift--for Synchron Transmission F 43546/RT 34000 8.85, PA0 ZF-Typenblatt Automated Preselection Shifting Device (AVS) for Synchron Transmission F32437/RT 3431-8.85, PA0 Electronic-Pneumatic Shifting Device (EPS) Trucks Daimler-Benz, AG, Order No. 6510302300, of 3.86 Scania - shift gears easier with a computer, page 4, column 2, second paragraph.
In all of these embodiments, the opening and closing of the clutch, and consequently of the drive trains between the engine and the transmissions, continues to be accomplished by the driver through the clutch pedal. While the driver knows when the gear is engaged as a consequence of direct contact with the shifting means in the transmission when gears are shifted by a gear shift linkage, that information, with the actuation of the gearshift lever and the gear shift linkage, is not in an auxiliary power actuated gear shifting mechanism. For operating the clutch at the proper time, and especially for closing the clutch after the shifting of gears in the transmission has been completed, response signals to the driver such as acoustical, optical and a physical feel are known.
After the conclusion of the shifting procedures in the transmission, the driver train can be closed again by the driver. The effort in the prior art devices to close the drive train as quickly as possible can result in difficulties. For example, if the driver doesn't wait for a response signal that a gear has been engaged in the transmission but closes the clutch without a gear having been shifted, the transmission will be in the neutral position. In such a case, the drive train is acutally not closed, although the clutch is in the closed position. Repeat shifting of gears by means of the clutch pedal is rendered difficult in most cases because all the gears have to be synchronized again before the gear shifting takes place. Thus the speeding up of the gear shifting process desired by the driver is delayed as a result of such procedure, or, a shifting of gears is prevented entirely by further incorrect operation.